This invention relates to an assisted braking device of the kind comprising a master piston mounted slidably in a master cylinder, pilot means including a pedal mounted on a pivoted pedal lever, assisting means comprising a motor, one movable element of which is adapted to cooperate with the master piston via interconnecting means, an assistance energy source, a distributor adapted to supply the motor with assistance energy from the said source, control means adapted to control the distributor in response to the actuation of the pilot means and comprising an arm and a connecting rod, the arm acting on a movable element of the distributor and being articulated on the said interconnecting means, the connecting rod connecting the pedal lever to the arm via two articulation points, and safety means which are actuated if the assisting means break down, so as to displace the master piston when a force is exerted on the pedal.
In the known devices of this kind, particularly those where the assistance system has a considerable effect, if the assistance system breaks down the driver may have to depress the pedal with an excessive force, so that these devices are not sufficiently safe.
In general, the solutions proposed hitherto for reducing the force which must be exerted by the driver when the assistance system is defective are unsatisfactory, since they still require considerable muscular strength on the part of the driver.
This invention relates to an assisted braking device wherein the contribution made by the driver's direct action on the pedal when the assistance breaks down is made safely and with moderate effort, thanks to a very simple, robust construction.